TEHRAN, October 11 -This mural is like a giant puzzle – more than 400 feet wide to be exact – and some of its missing pieces may never be found.

TEHRAN, Young Journalists Club(YJC) -World War I Museum hoping to uncover lost pieces of iconic mural.This mural is like a giant puzzle – more than 400 feet wide to be exact – and some of its missing pieces may never be found.

But that's not stopping the National World War I Museum and Memorial in Kansas City from trying to collect the remnants of the Panthéon de la Guerre, an iconic work commemorating about 6,000 allied figures from the Great War.

"People are amazed when they see it," senior curator Doran Cart told Fox News, whose museum is displaying a smaller version of the painting after it shifted ownership following World War I, was cut apart and then repurposed by an American artist.

“It is still an important mural even though it’s not as large as it once was, it still contained this whole idea of honoring the allies," Cart said.

The original painting was completed in Paris in 1918 by around 140 artists working under the guidance of French artists Pierre Carrier-Belleuse and Auguste Gorguet. In a specially built octagonal building to house the painting, artists pieced together a 402-foot-long circular canvas, which was also 45 feet high, making it one of the largest murals in the world.

“The artists’ work progressed under the depressing atmosphere of many military reversals – at times the gloom was heavy – the thousands of casualties in an apparently hopeless struggle did not build up a very spirited artistic atmosphere,” American soldier Daniel MacMorris, who later revised the work, wrote in a 1958 letter to a reporter at Britain’s Daily Telegraph. “They kept doggedly at it, like men who are determined to finish the embellishment of a great tomb.”

The Panthéon de la Guerre (translated Pantheon of War) contained 3,000 actual portraits of French military men and around three million people viewed the painting in Paris until it was taken down in 1927, according to MacMorris.

The original Panthéon de la Guerre arriving in Kansas City in 1957. (National World War I Museum and Memorial )

It then made its way across the Atlantic for a U.S. tour, stopping in New York, Washington, D.C., and Chicago’s World’s Fair in 1933-34 before being stored outside in a 55-foot crate in Baltimore.

William Haussner, a Baltimore art collector, restaurant owner and World War I German soldier, scooped up the painting at a local auction in 1952 for $3,400,.

"He kind of rearranged it. Instead of the French being in the middle, he put the Americans in the middle."

- World War I Museum Senior Curator Doran Cart

“He tried every possible avenue to get some organization to take it over and install it in its original form in a suitable building,” MacMorris wrote. “Over many years there seemed to arise several possibilities but no one actually did anything about it. It was deteriorating in a box in outdoor storage all the time and Mr. Haussner was paying $100 per month storage.”

Haussner had one look at the painting a year later, as he hired a 48-foot long trailer truck, three cranes and 22 workmen to bring the Panthéon de la Guerre to a parking lot and unroll it, LIFE magazine reported.

“I think it’s real pretty,” Haussner was quoted as saying as he spent hours walking up and down the artwork.

Artist and World War I American soldier Daniel MacMorris working with helpers to re-arrange the painting. (National World War I Museum and Memorial)

But over time, the elements took their toll on the mural and left portions of it gone forever.

“While it was laying outside, the sky and the battlefields -- which were two thirds of the painting -- were basically destroyed by the weather,” Cart told Fox News.

MacMorris, who worked at an art institute at the time, was able to convince Haussner to donate the painting to the Liberty Memorial Association in Kansas City in 1957, where it would finally get a home – but it would have to be showcased on a smaller scale. The Association owns the Museum.

“Had we not acquired it for Kansas City it seemed doomed for eventual destruction in the hands of some junk dealer,” he said.

MacMorris photographed the painting and cut some figures out of the photos while trying to decide how to downsize the massive artwork. He then took scissors and a paintbrush to the canvas.

“He squeezed this large painting into this current space which is about 40 feet long and 13 feet high,” Cart told Fox News. “He kind of rearranged it. Instead of the French being in the middle, he put the Americans in the middle. In the original, the Americans were at the end since they came in late in the war in 1917.”

MacMorris preparing the painting for its new home. (National World War I Museum and Memorial )

The artist also painted new faces into the mural: Carrier-Belleuse and Gorguet, former presidents Harry Truman and Franklin Roosevelt, and a Woodrow Wilson-like quote.

The revised Pantheon made its debut at the museum in 1959 after more than two years of work.

MacMorris said the American focus of his work was to pay tribute to Wilson’s efforts to form the post-World War I League of Nations.

“The purpose of my rearrangement is not the glorification of the U.S.A. nor the dimming of any other nation’s glory but, instead, to render homage to Woodrow Wilson and the League of Nations,” he said. “The exaltation of the brotherhood of man, and the suppression of tyranny – in other words the inception of the United Nations of today.”

The unused scraps of the Pantheon were either thrown out or given away – some back to Haussner, who put them up in his restaurant until he died. Other pieces were handed to art students who helped MacMorris with his vision and influential Kansas City residents.

Cart said the museum is hoping to collect as many of these missing pieces as possible to show them in exhibitions in person and online. Some -- like the large remnants Haussner had -- are still out there somewhere.

The museum doesn’t have a specific number as to how many pieces exist, but believes there are “dozens and dozens of fragments.”

One of the more recent submissions has been a several foot-wide piece of a French cavalry soldier riding on a horse, Cart said. Other fragments in the museum’s archives have been put on display in the past.

“Over the years… we have acquired many fragments that were removed and people were getting up in age and they all knew MacMorris, [so] they donated back to the museum,” Cart told Fox News. “We never really know when these are going to turn up.”